1. Field of the Invention
The invention relates to a production installation for assembling and/or processing structural components made up of several individual parts wherein the individual parts and/or components are disposed and/or assembled and/or processed on pallet trays which are disposed, preferably interchangeably, on carriages which are guided along the conveyor track of a conveyor device in which the conveyor track has parallel conveying paths extending in sections parallel to a main conveying path and connected by transverse conveying paths to the main conveying path.
2. Description of the Prior Art
In installations of this type. a basic distinction can be made between so-called loosely concatenated and rigidly concatenated installations. In loosely concatenated installations, the workpiece carriers or carriages are moved along the installation completely independently of one another and, in the event that a device in a single workstation breaks down, for a specific period of time this has virtually no effect on the activity of the other workstations. In rigidly concatenated installations, the workpiece carriers are interconnected in their movement so that, if faults arise in the vicinity of one workstation, all the workpiece carriers and all the workstations are blocked. Each of the two types of installation has its own range of application, the rigidly concatenated installations being used where only a few workstations are concatenated since the total utilization rate is a product of the utilization rates of the individual workstations. Loosely concatenated installations are generally used to concatenate a multiplicity of workstations, e.g. up to 40 or more, since in this case the utilization rate is then a value compounded from the individual occurrences of faults rather than the product of the utilization rates in the individual stations.
Many different installations with loose concatenation are already known--for example, from my U.S. Pat. Nos. 4,681,043, 4,762,218, 4,619,205, 4,530,287 and 4,492,297--which have proved successful in practice for concatenating a plurality of workstations. The workpiece carriers or carriages are in each case guided along lateral and vertical guideways independently of one another, and appropriate use of conveying rollers pressed against the side surfaces of the workpiece carriers ensures lateral and vertical guidance of the workpiece carriers without any play. Thus, accurate positioning of the workpiece carriers is achieved throughout the entire course of such an installation in cooperation with the drive means.
It is also known from my U.S. Pat. Nos. 4,884,330 and 5,103,963 to arrange the individual parts at as early a time as possible in a predetermined order which is to be maintained up to the point of their assembly in a workstation or processing station. For this purpose, the individual parts are individually deposited into unit receivers and are moved in a workstation or processing station into a reference position relative to an assembly workpiece carrier which is similarly an independently movable carriage whereupon the individual parts are removed from the unit receiver and are assembled or processed on the assembly workpiece carrier or an assembly location provided there. A work area which is separated from the workstations or processing stations, possibly with storage devices interposed, is provided for fitting the individual parts into the unit receivers. This process and apparatus have proved eminently successful in practice for fully automated processing and assembly processes although it has proved difficult to achieve a combination of manual and fully automated assembly processes within the same installation using this process and this apparatus.
The aim of the present invention is to provide a production installation of the type mentioned initially which permits flexible adaptation even to components which are to be assembled in smaller piece numbers, both in terms of the individual parts required and in terms of the tools required, and which should moreover be as inexpensive as possible to manufacture while having a high reutilization rate.
The aim of the invention is achieved in that there is associated with, parallel to and directly adjacent to the parallel conveying path, a subsidiary conveying path which is connected preferably by junction stations to the transverse conveying or parallel conveying path and/or the main conveying path. This arrangement of the parallel conveying path and a subsidiary conveying path directly alongside it creates the possibility of providing several workpiece carriers or pallet trays in the handling or working range of an operator for manipulating parts or carrying out assembly processes but at the same time also makes it possible to position the grab holders, in which individual parts are held in readiness for assembly or manipulation, for the operator in the manipulation range in question and at the same time to change them quickly. In an astonishingly simple manner, this creates the possibility of feeding the correct individual parts required for individual assembly processes to the operator and, if necessary, of precisely determining the number of parts, thereby preventing faulty assembly especially in the case of components having a small number of parts and different individual parts and also; allowing a wide variety of types of component to be perfectly processed or assembled.
According to a specific embodiment, the subsidiary conveying path is disposed on the side of a parallel conveying path remote from an operator and a storage conveying path is associated with this subsidiary conveying path, preferably between it and the main conveying path, with the result that the carriage for the pallet tray, on which the manipulation or assembly processes are carried out, is located closer to both operators than the subsidiary conveying path on which the parts for processing are placed in readiness or the grab holders are positioned.
It is further possible for an adjustable safety device to be disposed between the parallel conveying path and the subsidiary conveying path, said safety device preferably being formed by a guard plate which is disposed below a conveying plane of the subsidiary conveying path and is adjustable by means of a drive at right angles to the conveying plane into a position projecting out over the conveying plane, this being a simple means of preventing the operator from reaching into the region of the subsidiary conveying path, thereby permitting fully automatic movement of the carriages operating there and of the tools disposed thereon and allowing the use of conveyor devices which cannot be used to operate carriages in locations where manual work is carried out.
This is also possible for the reason that each change of type requires the work to be interrupted anyway and in order that the operator does not need to intervene in the region of the subsidiary conveying path during this process of changing type. It is also advantageous if this guard plate is disposed below the conveying plane of the subsidiary conveying path since this does not obstruct the work of the operator and it also does away with an oppressive guillotine-like overhead arrangement and the psychological stress on the operator which this entails.
According to a further development, it is provided that containers for individual parts are disposed on the carriages in the subsidiary conveying path, thereby allowing the operator to work with equipment he is familiar with, e.g. containers in the form of grab holders, and yet affording the advantage of rapid interchangeability of containers when assembling different parts or types of component.
It is also advantageous if the transverse and/or subsidiary and/or parallel conveying paths are connected to stand-by conveying paths since carriages with superstructural parts or pallet trays or grab holders, which are required, for example, only for a short duration or for quite specific manipulation processes or for retooling of the workplace or of the handling or processing equipment disposed in the workplace, can easily be held in readiness or used in the stand-by conveying paths.
According to a further embodiment, a pallet tray in the form of a retooling pallet having receivers for tools or grab fingers, text and/or setting devices and/or replacement equipment and possibly retooling parts is disposed on the carriage, thereby substantially facilitating the adaptation of a handling device for manipulating or assembling or processing different parts and inspection thereof and also, for example, the adjustment of measuring devices, which are connected to the handling and processing devices, by means of standard measuring instruments or the like and dispensing with the need for the usual outlay for additionally disposed changing devices through the use of standardized carriages with conveying paths. As a result of the direct placing together of the conveying paths, it is also easily possible to achieve manipulation of the piece parts or components with just a few positioning movements.
It is also possible for the stand-by conveying path to be connected by the main conveying path to the parallel conveying path so that central stand-by conveying paths can be disposed with the result that the carriages, which are parked therein and on which the containers or pallet trays, tools or the like are disposed, can easily be fed to different parallel conveying paths.
It is also advantageous, however, if a central stand-by conveying path is provided for several conveying paths since the carriages frequently required for each assembly machine and having different tools, measuring instruments and the like can then be centrally parked.
According to another embodiment, the carriage having the retooling pallet is movably disposed on the subsidiary conveying path, thereby allowing the operator or the handling appliances and machines disposed in the vicinity of the workstation or processing station to have direct access at any time to the retooling pallet.
According to a further embodiment, a return conveying path is disposed between the parallel conveying path and the main conveying path, thereby allowing the alternately required carriages with the containers or pallet trays disposed thereon to be interchanged very rapidly and stored in the intervening period in the direct vicinity of their area of use.
It is also possible for the storage conveying path and/or the return conveying path simultaneously to form the stand-by conveying path, with the result that the storage or return conveying path can be used at the same time as a stand-by conveying path.
However, it is also advantageous if the parallel conveying path and the subsidiary conveying path are directly adjacent to one another, with the safety device interposed, and the storage conveying path or the return conveying path is disposed at a distance from these since this means that the carriages with their superstructural parts can move in the storage conveying path or return conveying path without endangering the operator even if the safety devices have been released or removed and the manual work sequence is being carried out in the parallel conveying path and the subsidiary conveying path directly adjacent to it.
Furthermore, it is also possible for a feed device for the carriages, which can be independently acted upon by the other feed devices, to be associated with the operator in the parallel conveying path, thereby additionally preventing any risk of injury to the operator while the carriages within his operating range are being manipulated.
According to a further embodiment, a parallel conveying path and at least one subsidiary conveying path are disposed immediately adjacent and parallel to one another, and a handling device is arranged so as to span these conveying paths at right angles to the conveying direction, thereby allowing the manipulation times to be kept very short for shifting individual parts or carrying out operating processes which involve the carriages disposed next to one another on the two conveying paths and the superstructural parts disposed thereon.
However, it is also further possible for carriages having pallet trays to be disposed on the parallel conveying path and for a carriage having a pallet tray with assembly receivers, or a retooling pallet and possibly a drive pallet to be disposed on the subsidiary conveying path, thereby allowing the parts to be processed on the assembly receivers to be easily supplied from the carriages on the subsidiary conveying path.
According to another advantageous construction, two subsidiary conveying paths are associated with the parallel conveying path, parallel and immediately adjacent to it, and carriages having pallet trays with component and/or unit receivers and possibly an assembly receiver are disposed movably along the conveying direction on the parallel conveying path and carriages having pallet trays for a plurality of, in particular identical, individual parts are provided movably along the guideways on a subsidiary conveying path and a pallet tray is movably disposed on the further subsidiary conveying path and has at least grab tools or grab fingers and possibly assembly receivers and/or receivers for incorrectly processed components, thereby allowing the working times for an assembly cycle to be kept very short and at the same time keeping down the necessary cost of manufacturing such production installations.
According to another embodiment, the containers for the individual parts or the pallet trays are detachably mounted on the carriages by means of coupling devices of an identical type, thereby allowing the different container and pallet trays to be disposed and reliably transported in the correct position on the same carriages.
It is also advantageous if the coupling device has centering elements, e.g. centering pins, for the containers and pallet trays since it is then possible, independently of the coupling device, to achieve a precise alignment of the containers and pallet trays and dimensionally accurate positioning and centering on the carriages.
However, it is further possible for the containers to be provided with preferably adjustable or swingable chutes, preferably in the form of gripping cups, thereby allowing the quantity of individual parts made available to the operator to be easily regulated and allowing the outlet opening in the container to be closed simultaneously by the chute, resulting in easy transportation on carriages without any loss of individual parts.
It is also advantageous if the containers for the individual parts take the form of wash tanks because then the individual parts to be supplied for assembly can be washed directly prior to the assembly or processing process and supplied for this process without further manipulation.
However, it is also possible for the chutes to be provided with guide channels for isolated individual parts, said channels being disposed on the same level as corresponding guide channels on pallet trays or on the same level as assembly receivers, since this means, particularly in the case of cleaned parts, that these parts need be touched as little as possible and also the time required for correctly positioned supply of the individual parts on the pallet trays or to the assembly receivers is kept very short.
According to a further embodiment, a plurality of carriages provided with containers for individual parts are disposed downstream of one another on the subsidiary conveying path and are preferably positionable by means of positioning devices which are independent of one another. This means that several containers disposed on different carriages can be moved along the subsidiary conveying path always into a different stand-by position in order, for example, to provide the operator with the required individual parts at the same spot in each case.
It is, however, also advantageous if the carriages and/or the pallet trays and/or the containers are provided with coding elements with which coding devices disposed along the various conveying paths are associated as this substantially simplifies automatic management and accurately targeted supply to the individual conveying paths without manual control.
It is, however, also possible for transfer devices for data and/or energy to be disposed in the storage and/or stand-by and/or subsidiary conveying path and to be associated with transfer elements of the transfer device on the carriages and/or the containers and/or the pallet trays, thereby allowing, for example, processing data regarding the individual workpieces or the like disposed on the pallet trays to be stored directly onto these and to be read at any point into an information network or into memory units, processing devices or handling devices. It is further possible to display these data on a screen assigned to the operator so that he can, for example, use or assemble the individual parts required according to measuring results. Above all, when using transfer devices which also permit contact-free transmission of drive energy to the carriages or corresponding superstructural parts, it is possible to undertake certain adjustment operations in the course of processing or supply or transport if an energy-storing device, e.g. a battery, is additionally disposed on the running mechanism.
In a preferred form, it is possible for the transfer device to include an energy field which is built up between the transfer elements so that sufficient energy can be supplied to the individual carriages and the superstructural parts disposed thereon, such as pallet trays, containers or the like, without obstructive contacts and the problems these entail.
It is also further possible for the carriages and/or the grab holders and/or the pallet trays to be provided with display elements, in particular plain-text displays, so that it is possible at any time to check manually whether the processing or handling operations are being correctly carried out.
It is, however, also advantageous if the pallet tray is provided with one or more, possibly different, assembly receivers. This makes it possible to carry out the assembly processes on easily interchangeable retooling pallets and to use the other carriages, with the pallet trays or containers disposed thereon, to transport the individual parts or the components to be assembled between the individual workstations, thereby keeping down the cost of the assembly receivers, which are to some extent very expensive owing to their high precision, by reducing their number.
It is also advantageous if the retooling pallet and/or a pallet tray is provided with receivers for faulty components, making it easy to separate out components, in which assembly has been incorrectly carried out or incorrect individual parts have been assembled, and convey them separately to an aftertreatment station or special place of deposit.
According to another embodiment, control mechanism for a coupling device is disposed on the retooling pallet and/or a drive pallet associated with the retooling pallet between a grabbing tool and/or grab tray and a handling device. The advantage of using a separate drive pallet, which can be used to activate control mechanisms disposed on another carriage, is that one and the same drive pallet can be used to supply drive energy to different positions of another carriage or the superstructural parts disposed thereon.
It is, however, alternatively possible for the drive pallet to be connected to its own energy supply and/or control device or to a transfer element of a transfer device for energy and data at least in the region of the handling device, so that the drive pallet can be used at various points to act upon various actuating drives and, in the case of use of an energy-storing device, it need be re-supplied with energy and the necessary data for carrying out the next operating tasks only in its stand-by region.
According to a preferred embodiment, the grab device is provided with grab fingers which have a longitudinal guideway for grab trays and locking devices are associated with these longitudinal guideways in the grab fingers, making it possible to achieve precise guidance of the grab trays in the grab fingers and hence a rapid and easy interchange without expensive independent adjustment mechanisms.
It is also possible for the locking device to have a locking plunger or an unlocking piston which is disposed so as to be movable in a direction at right angles to the longitudinal guideway and cooperates with a ball catch or a pivoted lever so that unlocking of the grab trays can be achieved automatically by the grab device being lowered and the grab fingers being supported on a pallet tray or a retooling pallet.
Finally, it is also possible for support rails disposed on a pallet tray to be associated with the locking plunger or unlocking piston, said support rails having at least a length which corresponds, in the case of a length of the longitudinal guideway corresponding to the breadth, to the breadth and being disposed centrally relative to receivers for the grab trays, so that removal and insertion of the grab trays is possible by moving the carriage having the pallet tray or transfer pallet relative to the grab device.